甘蔗渣固态发酵产纤维素酶

以甘蔗渣和麸皮混合作为固态发酵产酶培养基,采用单因素优化实验对里氏木霉固态发酵产纤维素酶进行优化。结果表明,在50 m L体系培养基中,在底物绝干原料5.2 g、甘蔗渣与麸皮质量比7∶3、氮源((NH4)2SO4)7.5 g/L、产酶诱导物1.6 g/L、表面活性剂(聚乙二醇PEG6000)0.1 g、发酵起始p H 4.4、培养基中里氏木霉孢子接入量5×105个的条件下,温度30℃时发酵120 h,里氏木霉固态发酵产纤维素酶的酶活达76.39 IU/g,是起始优化前20.29 IU/g的3.76倍。     

解淀粉芽胞杆菌PC2产抑菌物质培养基及发酵条件优化

【目的】优化解淀粉芽胞杆菌PC2产抑菌活性物质发酵培养基及发酵条件。【方法】以马铃薯葡萄糖液体培养基为基础,依据发酵液对金黄色葡萄球菌抑菌圈的单因素试验结果,采用Box-Behnken响应面法优化发酵培养基,二次通用旋转组合设计,频率分析法优化发酵条件。【结果】影响发酵液抑菌活性的培养基主要组分为马铃薯、蔗糖和L-谷氨酸钠,最优发酵培养基配方为:马铃薯188.0 g/L,蔗糖22.0 g/L,L-谷氨酸钠1.80 g/L,培养基成本为0.81元/L;最佳发酵条件为:接种量6%、发酵温度30°C、装液量40 mL/250 mL、摇床转速185 r/min、发酵时间24 h、初始pH 7.0。优化后发酵液对金黄色葡萄球菌抑菌圈直径为30.82 mm,较优化前的18.22 mm增加了12.60 mm。【结论】优化后的培养基和发酵条件提高了解淀粉芽胞杆菌PC2发酵液的抑菌活性,为该菌株的工业化生产应用提供了依据。     

枯草芽胞杆菌B006产表面活性素的培养条件优化

芽胞杆菌产生的环脂肽类生物表面活性素surfactin具有重要抗菌、促进生物膜形成等功能,其含量和同系物组分构成影响其功能。为了提高芽胞杆菌B006产生表面活性素的产量,通过单因素实验和正交实验,测定了碳源、氮源和无机盐等营养物质及接种量、培养时间、装液量和初始pH值对芽胞杆菌B006摇瓶发酵产生表面活性素的影响;采用排油圈法测定发酵液中表面活性素的产量,采用HPLC-MS方法比较培养基优化前后surfactin的产量和组分含量。结果表明,适合芽胞杆菌B006摇瓶发酵产生表面活性素的培养基组成为:牛肉膏10 g/L、玉米粉15 g/L、硝酸铵3 g/L和氯化钠3 g/L;适合的培养条件为:初始pH值7.0、接种量10%、装液量60 m L/500 m L,发酵周期64 h。优化后surfactin的产量约为314.73 mg/L,比优化前提高了74.88%;surfactin各组分比例发生改变,其中C16和C17组分的含量明显提高,为优化前相应组分含量的1.64和8.34倍。优化的培养基组分和培养条件可明显提高芽胞杆菌B006菌株产生surfactin的产量,改变surfactin同系物组分的构成,为利用芽胞杆菌B006进行高活性表面活性素的工业生产和代谢调控研究奠定了基础。     

培养基组分对枯草芽胞杆菌产表面活性素的影响

表面活性素(surfactin)中的C15组分是表面活性素Surfactin异构体混合物中的重要活性组分,在表面活性、溶血活性、抗病毒活性和抑菌活性方面都有突出的表现。考察培养基p H、碳源、氮源、碳氮比、金属离子以及氨基酸等主要参数对枯草芽胞杆菌发酵产物surfactin中C15组分的影响,利用优化后的培养基(葡萄糖20 g/L、NH4NO32 g/L、K2HPO43 g/L、Na H2PO410 g/L、Mg SO40.02 g/L、Leu 1 g/L和p H 8.5),枯草芽胞杆菌BS-37发酵24 h,surfactin总产量达750 mg/L,其中C15组分达510 mg/L,占surfactin总量的68%。     

产脂肪酶重组枯草芽胞杆菌的发酵优化

笔者所在实验室前期筛选到1株产脂肪酶粘质沙雷氏菌,克隆其脂肪酶基因,构建重组枯草芽胞杆菌Bacillus subtilis 168/pMA5-lipA,成功实现了来源于粘质沙雷氏菌的脂肪酶基因在枯草芽胞杆菌中的表达。基于以上工作基础上,对B.subtilis 168/pMA5-lipA进行了摇瓶水平上的产酶发酵优化。首先通过单因素和正交试验确定了有利于产脂肪酶的最佳培养基成分,并对发酵条件进行了优化。结果表明:优化后的培养基组分为蔗糖35 g/L,玉米浆27.5 g/L,(NH4)2SO41.25 g/L,CaCl24 g/L,pH 7.0。在最优发酵培养基的条件下,37℃、160 r/min摇床培养33 h,每毫升发酵液中重组菌脂肪酶酶活可达98.6 U,是优化前的3倍。     

红曲霉液态发酵生产红曲色素的工艺优化

为提高红曲色素的液态发酵水平,降低生产成本,采用Plackett-Burman试验与Box-Benhnken试验对红曲霉MY-03液态发酵生产红曲色素的工艺条件进行了优化,获得了最佳工艺条件:葡萄糖50 g/L、蛋白胨58.07 g/L、Mg SO4 2 g/L、Na NO3 2g/L、Mn SO4 0.3 g/L、Zn SO4 0.1 g/L、装瓶量50.8 m L、接种量10.0%(V/V),于150 r/min、30℃恒温培养7 d,红曲色素色价可达342.24±2.88 U/m L,比基础培养基提高了86.9%。     

猪源屎肠球菌WEI-9的高密度培养

目的对分离自健康仔猪肠道的屎肠球菌(Enterococcus faecium)WEI-9的高密度发酵培养基进行响应面优化,为菌株WEI-9的工业化生产奠定基础。方法首先采用单因素试验确定最适高密度发酵培养基的碳源和氮源,随后采用Plackett-Burman设计筛选出影响菌株WEI-9发酵活菌数的显著因素,利用最陡爬坡试验得出显著因素逼近最大活菌数产量的响应区域,最后应用Box-Behnken设计和响应面分析法确定显著影响因子的最佳浓度。结果优化后的最适高密度发酵培养基成分和配比为:乳清粉21.34 g/L,蛋白胨21.94 g/L,Na AC·3H2O 5 g/L,柠檬酸铵2 g/L,K2HPO4·3H2O 2 g/L,Mg SO4·7H2O 0.2 g/L,Mn SO4·H2O 0.05 g/L,吐温-80 1 g/L,发酵液最高活菌数达到1.6×109CFU/m L,是相同条件下MRS培养基中活菌数的1.98倍。结论本研究实现了猪源屎肠球菌(Enterococcus faecium)WEI-9的高密度培养。     

硒对荷叶离褶伞菌丝体胞外粗多糖的影响及发酵条件优化

以亚硒酸钠为无机硒源,研究硒的加入对荷叶离褶伞菌丝体胞外粗多糖的影响并优化其发酵条件,选择培养基灭菌条件、添加硒浓度、发酵时间和初始pH值作为优化因素,研究硒在各因素不同水平下对荷叶离褶伞胞外粗多糖含量的影响。通过单因素试验和响应曲面法得到最佳发酵条件:在121℃,20 min对培养基进行灭菌,发酵液中添加2μg/m L Na_2SeO_3,发酵244 h,培养基初始pH值为7.0的条件下,发酵产生的胞外粗多糖含量为0.760 g/100 m L,较未加入硒(0.218 g/100 m L)和加硒未优化前的含量(0.755 g/100 m L)有所提高。研究结果表明,响应曲面法优化富硒荷叶离褶伞发酵条件可使胞外粗多糖含量大幅度提高。     

响应面法优化枯草芽孢杆菌NHS1产芽孢发酵培养

为提高枯草芽孢杆菌(Bacillus subtilis)NHS1菌株发酵液中芽孢含量,采用单因素试验与响应曲面法优化试验相结合的方式,对该菌发酵培养基中的碳源、氮源以及无机盐等组成成分进行了优化。通过单因素试验、Plackett-Burman试验、最陡爬坡试验以及BoxBchnken试验构建响应方程,得到方程为:Y=-3.30+3.853X1+0.0928X2+0.623X3-0.913X1×X1-0.00704X2×X2-0.0433X3×X3-0.0033X1×X2-0.0700X1×X3+0.00167X2×X3。利用该方程预测得到最优培养基:淀粉1.88 g·L~(-1)、Na Cl 6.83 g·L~(-1)、玉米粉5.60 g·L~(-1),酵母粉10g·L~(-1),蛋白胨10 g·L~(-1),牛肉膏15 g·L~(-1),葡萄糖2 g·L~(-1),Mg SO43 g·L~(-1)。利用优化培养基,在36℃、170 r·min~(-1)条件下摇瓶发酵72 h,芽孢数达到2.42×109cfu·m L~(-1),比优化前提高1.5倍。     

Determination of an economical medium for growth of Clostridium butyricum fermentum

本文重点在于提高酪酸梭状芽孢杆菌活菌数量,降低发酵培养基成本.通过对发酵培养基中不同碳源、氮源、生长因子等进行单因素研究,得到最佳培养基组成:可溶性淀粉10 g/L,豆粕(中性蛋白酶水解3 h)20 g/L,玉米浆3g/L.用此培养基在37℃培养24h,采用高层半固体琼脂试管法对酪酸梭状芽孢杆菌进行活菌计数,活菌数可达8.2×108 cfu/mL.培养基中添加K2HPO4 5g/L、MgSO4·7H2O 0.2 g/L、MnSO4·H2O 0.2 g/L培养32 h时,酪酸梭状芽孢杆菌芽孢转化率可达95％.     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.

     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.